1. Field of the Invention
This invention relates to a method and system for viewing at a client computer a series of three-dimensional virtual views, transmitted over the Internet, of a volume visualization dataset contained on one or more centralized databases.
2. Description of Related Art
The demand for easy access to medical scans is increasing and the expectation for a simpler and faster way to interpret these large scans is growing. Technology exists to present richer three-dimensional (3D) views from existing two-dimensional (2D) scans that may lead to better diagnosis and prognosis as well as improved patient care. However, the current solutions are impractical for 3D to be ubiquitous.
Computed Axial Tomography (CT) scans or magnetic resonance imaging (MRI) scans of a patient's body results in large 3D volume datasets that are time consuming when transported over the Internet. The scans are typically spaced two-dimensional planar cross-sections of the patient's body or a portion thereof, such as an organ. The scans of these or other objects may be stored as a volume visualization dataset in an otherwise conventional data storage medium accessible by a computer or other specialized processor. Assuming the scans are parallel images arranged in the sequence in which they are found in the scanned object, 3D virtual views of the volume visualization dataset are made by selecting a plane to be cut through the volume of the object at a particular location and angle. The selected plane may be parallel to the scans, or at any angle to the scans. The location may be anywhere within the scanned volume of the object. The 3D virtual image is a two-dimensional representation of the 3D object showing the desired perspective of view and may include images showing depth of or through the object in a direction normal to and behind the selected plane of view.
Generating dynamic 3D views requires processing of raw 2D scans into 3D and to isolate feature of interest from the raw scan. Therefore, for 3D to be available, either the user's computer or a dedicated server needs to be powerful enough to support this processing power and the 2D scans need to be directly available to the user's computer via a high speed communication link. Facilities such as Hospitals and Imaging Centers need to provide the software, hardware, and networking infrastructure and support the IT administration to allow their physicians access to 3D. This becomes expensive and adds an administrative burden that only a select few provide such a “luxurious” functionality to their physicians. The present invention overcomes this limitation by teaching a method and system of a common and centralized infrastructure, for receiving, storing, processing and viewing large medical scans via a low-bandwidth web portal where economics of scale can be applied generously.
Internet access via web portal particularly low bandwidth and high latency situation of rural area can hinder the user interactivity of information presented in 3D. Latency, i.e., delay in the time it takes for a packet of data to travel from one designated point to another in response to a request, is particularly problematic for users having low bandwidth Internet communication. Unless otherwise noted, the term “low bandwidth” refers to communication speed of no more than about 1.5 Mbps, and the term “high latency” refers to response time of more than about 125 ms. The user may request arbitrarily and dynamically generated views. This requirement normally mandates that raw scan data needs to be present on the user's computer for manipulation. For large 3D, four-dimensional (4D), or higher dimensional scans, the retrieving or raw scan for processing is impractical or impossible over low bandwidth network. (Scans in 4D can come in the form of time varying 3D scans, or as a result of combining two datasets, such as PET and CT scanners dataset combined in one. Also, when PET-CT are combined and have a time component, this can be termed a 5D scan, which involves very large datasets.) The publication by Klaus Engel on Remote 3D Visualization Using Image-Streaming Techniques teaches how volume visualization can be obtained via a client and server interaction over the web without having to retrieve raw scan on to user machines. However, such technique requires sufficient bandwidth and low latency network to present information at interactive frame rates. This presents a problem for rural areas to gain access to medical scans in advanced visualization format interactively.
Furthermore, medical service providers are required to keep medical records for six years or more and have to do so with utmost security and privacy. This becomes expensive and adds a management burden to facilities as there can be IT, physical space and cost administration limitations. The end effect is that a facility's operation remains an ad hoc process.